Receiver dehydrators are used in air conditioning and refrigeration systems to remover water and other impurities from oil and refrigerant commonly used in such systems. Receiver dehydrators which are also referred to as refrigerant filter dryers, conventionally include a desiccant core which serves as a filter element. The desiccant core is enclosed within a thin walled can or body. Cores are generally made of molded desiccant materials such as activated alumina. Molded cores are relatively brittle and may be subject to breakage if the receiver dehydrator is dropped during handing prior to installation. The core itself may also be subject to breakage due to vibration from nearby equipment. Damage may also result if the body of the receiver dehydrator is inadvertently struck by a wrench or other tool during servicing of the refrigeration or air conditioning system.
If the core of a receiver dehydrator is broken, its filtering and water removal efficiencies will be adversely impacted or eliminated. Small pieces of the core may also escape and travel into other areas of the system. These core fragments may result in damage to other components of the system.
Others have previously developed receiver dehydrators with enhanced impact and vibration resistance. Once such unit is the Catch All.RTM. receiver dehydrator produced by Sporlan Valve Company. This receiver dehydrator uses a cylindrical core housed within a cylindrical thin walled body. The core is positioned inside the body and has a metal plate affixed to a first end of the core. A metal leaf spring applies force to the plate. An opposed second end of the core is positioned on a relatively rigid, ring-shaped seal. A rigid centering strip is positioned between the outside surface of the cylindrical core and an inner wall of the body. The centering strip prevents movement of the core at the second end. The force applied by the spring holds the core in compression. This helps to hold the core intact in the event of shock or vibration. Applicants have found, however, that impacts, particularly those transverse to a longitudinal axis of the core, will result in damage. This prior design also employs a fine mesh screen adjacent an outlet end of the receiver dehydrator to minimize the possibility that fragments of a damaged core will pass out of the unit and into the remainder of the system.
Parker Hannifin Corporation, the assignee of the present invention, has also previously developed receiver dehydrators that have enhanced resistance to damage due to impact and vibration. These designs include a core block which has a projection at a first end. The projection of the core block is nested in a recess in a spring loaded plate. The plate has three equally spaced radially extending fingers which extend to adjacent an inner wall of the cylindrical body of the receiver dehydrator. The opposed second end of the core block is also spring loaded and is positioned on a perforated disc. An outer perimeter of the core block at the second end includes flutes or projections, which contact the interior surface of the cylindrical body. While this construction is also resistant to shock and vibration damage, the core block is nonetheless subject to breakage in many circumstances.
Thus, there exists a need for a receiver dehydrator which has enhanced resistance to damage due to impact and vibration.